This invention relates to the field of water closets and is particularly concerned with apparatus and a method for conservation of water during the flushing cycle.
It is known in the prior art to conserve water by evacuating the waste water from the bowl in such a manner that there is a minimum mix of the introduced rinse water with the waste water that is evacuated, thereby minimizing the loss of the introduced water into the drainage system. This has been done in the past in flush systems in which a partial vacuum is introduced into the drainage trap of the toilet to initiate siphoning of the waste water from the toilet bowl after which the rinse water can be introduced. Systems of this type are shown for example in U.S. Pat. No. 210,003, patented Nov. 19, 1878 in the name of Bunting, Jr., and U.S. Pat. No. 4,115,883, patented Sept. 26, 1978 in the name of Dauvergne. Apparatus of this type shown in these patents have drawbacks in that they require check valves in the trap to prevent return flow of gases or liquids from the sewer line. Further, they require other actuating or control apparatus which may become faulty during operation and are more costly to produce.
Other approaches have also been made in an effort to reduce the volume of flush water that is required. One such approach is disclosed in U.S. Pat. No. 3,843,978, patented Oct. 29, 1974 in the name of Ragot, wherein electrically operated switches operate a high-pressure water jet in the trap to initiate the flushing action and a high-pressure water jet in the bowl to generate swirling, scouring effect. Electrical sensors are required to regulate and control the jets and refill. Again, complex and costly apparatus is required for toilets of this type.
Still another approach is disclosed in U.S. Pat. No. 3,984,878, patented Oct. 12, 1976 in the name of Grasseschi wherein the flushing operation includes a high-pressure stream that occurs in two phases, a first phase which has high momentum and evacuates the bowl, and a second phase which has low momentum and refills and reseals the bowl. Again, this apparatus is complex and costly.
It is also known in the art to utilize a flushing system wherein a jet of water is utilized to initially evacuate the bowl, and rinse water, which flows in a parallel path, is used for rinsing the bowl. A system such as this is shown in U.S. Pat. No. 3,010,115, patented Nov. 28, 1961 in the name of Wiggs. However, in this flushing system there is no timing of flow or metering of any significant consequence that will reduce to a minimum the amount of flush water that is utilized so that optimum conservation can be realized.
Thus, the prior art structures fail to disclose a simple form of flush system which can use conventional toilet tank fill valves and flush handle and flush ball mechanisms and still provide maximum conservation of flush water without the need of adding expensive and complex additional valving and control mechanisms therefor. It is known to use tank fill valves that employ the hydraulic forces of the supply water to provide positive opening and closing of the valve. Valves of this type can be used in the present invention and are shown, for example, in U.S. Pat. No. 3,895,645, patented July 22, 1975; U.S. Pat. No. 4,065,095, patented Dec. 27, 1977; and U.S. Pat. No. 4,180,096, patented Dec. 25, 1979, in the name of Johnson.